1. Field of the Invention:
This invention relates to lens mountings with an optical element holding device making it possible to adjust the orientation and axial alignment of an optical element.
2. Description of the Prior Art:
An example of a prior known adjusting device is shown in FIGS. 1A and 1B. This device has generally been used for the objective lens of a telescope. The objective lens L is fixedly carried in a cell A having an integral flange A'. B is a body tube. C and D are a screw fastener and a space adjusting screw respectively.
The lens cell A is fixedly secured to the body tube B by three screw fasteners C, while the tips of three adjusting screws D abut on the shoulder of the body tube B to hold the lens cell A at a certain distance from the shoulder of the body tube B. By selectively turning the screws D, the optical axis of the lens L can be brought into coincidence with the axis of the body tube. But, because all the screws must be handled, the satisfactory adjusting operation can be done only by the skillful artisan. Another drawback is that after such adjusting operation has been completed, the resultant axial position of the lens often differs from the specified one.
FIG. 2 illustrates another example of the prior art wherein the cell E containing the objective lens L is fixedly secured to the body tube B by screw fasteners G. In this case, positioned between the flange E' of the lens cell E and the shoulder of the body tube B is a spacer F such as a tin foil to adjust the orientation of the lens axis. This adjusting device has not only the drawback of poor productivity, but also a problem that the adjustment cannot be carried out continuously.